Here is a suggested Study time table for the WBCS aspirants which can help him plan out his studies for giving the exam!
Start in August
August and September: Finish your first Optional Subject preparation for the WBCS(MAIN). The "Optional Subject" is the one you will be giving in the Mains!
October to December: Devote fully to the Preparation of General Studies and English for the WBCS(Prelims).January should be spent exclusively for Prelims. A selective and precise coverage of syllabus for the prelims is required.
Give your Preliminary Exams!
Take a break after the Prelims for 10-15 days. Relax and re-energize yourself for the last six months.
Complete the first Optional where you left it at the time of Prelims. This should be done by the end of March. Also prepare for your "English” paper and "Indian Language " paper now.
Give April to June to your second Optional . Also prepare for your "Arithmatic” paper now. If you are weak in English or Arithmatic, you will have start thes preparation a little earlier!Prepare all your General Studies including current events in June and leave July for Revision.
Give your mains!
After your Mains are over, take a break for say a month or so. Just keep reading Newspaper/Magazines (The Telegraph & Times of India's international events are a good combination).
From September you should start preparing for your round two. Prepare the topics you could not do in your 1st attempt and try to cover any, new areas where you feel you were weak. By April, you should be fully prepare to tackle the Mains once again (hopefully you won't need it, still it pays to be prepared).In between the results of the WBCS(Main) come out and immediately afterwards you should start your interview preparation.
Give your interview! Get selected! OVER!
Best Of Luck!